[UE5 Branch] Traffic Light Generation Issues: Hardcoded Emissive Materials & Actor Duplication on XODR Load

[mingxili2208]

Description:
I am currently working with the ue5 branch of the carla-digitaltwins tool to generate scene maps using OpenStreetMap data. After generating the map and migrating it to a CARLA project, I encountered two critical issues regarding the Traffic Light (TL) actors, which prevent them from functioning correctly in the simulation.
Environment:

• Branch: ue5
• Tool: carla-digitaltwins
• Workflow: OpenDRIVE Generation -> Migrate to CARLA Project -> Load Map with .xodr
  Observed Behavior:

1. Static Meshes are "Always On" (Material Issue):
   The Traffic Light Static Meshes generated by the tool have their material emissive properties hardcoded to a high value for all three bulbs (Red, Yellow, Green) simultaneously.

   • Result: The traffic lights appear visually fully lit at all times.
   • ** It appears the materials are not generated as Material Instances with exposed Scalar Parameters (e.g., Emissive_Red, Emissive_Green) initialized to 0. Instead, they are baked with high luminance.（The lumen value is the same as the lumen value of the directional light I imported to solve the problem of no light source in the generated map. I am not sure if it is related.）

2. Actor Duplication / Logic Conflict:
   When the generated map is loaded in CARLA alongside its corresponding .xodr file, CARLA's standard OpenDRIVE parsing logic automatically spawns a new, functional Traffic Light actor (e.g., BP_TLOpenDrive) at the exact same coordinates as the generated Static Mesh.

   • Result:
     • A Static Mesh (generated by Digital Twin) exists at the location: All lights ON.
     • A Dynamic Actor (spawned by CARLA at runtime) exists at the same location: All lights OFF (or functioning logically, but obscured).
     • This results in visual clipping/z-fighting and logically unusable traffic lights, as the functional actor is visually overridden by the "always-on" static mesh.